Along with the development of the network era, many advertisements are released and promoted on the Internet. Various advertisements can be seen on almost every webpage. Even when a user turns off an advertisement, said advertisement would reappear on the webpage after a period of time.
At present, all browsers have the function to filter advertisements. The common filtering means is to filter advertisements by using the Cascading Style Sheets (CSS) hiding method. Its principle is that a browser hides an advertisement element by forcing the display attribute of the advertisement element to be none. It is the simplest and most effective way of advertisement filtration through CSS.
With respect to the way of advertisement filtration through advertisement hiding by CSS, however, an author may take some countermeasures on the filtered advertisements to prevent the advertisements from being filtered. For example, a timer may be activated to inspect regularly whether the display attribute of an advertisement element is none and detect whether said advertisement is hidden. When the display attribute is none, the display attribute of the advertisement element is reset to: blocking said advertisement display, such that the hidden advertisement is displayed again. In view of the situation above, therefore, the existing way of hiding advertisements through CSS to achieve advertisement filtration cannot effectively block advertisements.